bootstrap: support configure-time user-land snapshot

configure.py

@@ -788,6 +788,13 @@
     default=False,
     help='node will load builtin modules from disk instead of from binary')
 
+parser.add_argument('--node-snapshot-main',
+    action='store',
+    dest='node_snapshot_main',
+    default=None,
+    help='Run a file when building the embedded snapshot. Currently ' +
+         'experimental.')
+
 # Create compile_commands.json in out/Debug and out/Release.
 parser.add_argument('-C',
     action='store_true',
@@ -1216,6 +1223,18 @@ def configure_node(o):
 
   o['variables']['want_separate_host_toolset'] = int(cross_compiling)
 
+  if options.node_snapshot_main is not None:
+    if options.shared:
+      # This should be possible to fix, but we will need to refactor the
+      # libnode target to avoid building it twice.
+      error('--node-snapshot-main is incompatible with --shared')
+    if options.without_node_snapshot:
+      error('--node-snapshot-main is incompatible with ' +
+            '--without-node-snapshot')
+    if cross_compiling:
+      error('--node-snapshot-main is incompatible with cross compilation')
+    o['variables']['node_snapshot_main'] = options.node_snapshot_main
+
   if options.without_node_snapshot or options.node_builtin_modules_path:
     o['variables']['node_use_node_snapshot'] = 'false'
   else:

lib/internal/bootstrap/pre_execution.js

@@ -14,6 +14,7 @@ const {
 const {
   getOptionValue,
   getEmbedderOptions,
+  refreshOptions,
 } = require('internal/options');
 const { reconnectZeroFillToggle } = require('internal/buffer');
 const {
@@ -26,7 +27,10 @@ const { Buffer } = require('buffer');
 const { ERR_MANIFEST_ASSERT_INTEGRITY } = require('internal/errors').codes;
 const assert = require('internal/assert');
 
-function prepareMainThreadExecution(expandArgv1 = false) {
+function prepareMainThreadExecution(expandArgv1 = false,
+                                    initialzeModules = true) {
+  refreshRuntimeOptions();
+
   // TODO(joyeecheung): this is also necessary for workers when they deserialize
   // this toggle from the snapshot.
   reconnectZeroFillToggle();
@@ -78,15 +82,23 @@ function prepareMainThreadExecution(expandArgv1 = false) {
   initializeSourceMapsHandlers();
   initializeDeprecations();
   initializeWASI();
+
+  if (!initialzeModules) {
+    return;
+  }
+
   initializeCJSLoader();
   initializeESMLoader();
-
   const CJSLoader = require('internal/modules/cjs/loader');
   assert(!CJSLoader.hasLoadedAnyUserCJSModule);
   loadPreloadModules();
   initializeFrozenIntrinsics();
 }
 
+function refreshRuntimeOptions() {
+  refreshOptions();
+}
+
 function patchProcessObject(expandArgv1) {
   const binding = internalBinding('process_methods');
   binding.patchProcessObject(process);
@@ -95,7 +107,8 @@ function patchProcessObject(expandArgv1) {
 
   ObjectDefineProperty(process, 'argv0', {
     enumerable: true,
-    configurable: false,
+    // Only set it to true during snapshot building.
+    configurable: getOptionValue('--build-snapshot'),
     value: process.argv[0]
   });
   process.argv[0] = process.execPath;
@@ -111,6 +124,12 @@ function patchProcessObject(expandArgv1) {
     }
   }
 
+  // We need to initialize the global console here again with process.stdout
+  // and friends for snapshot deserialization.
+  const globalConsole = require('internal/console/global');
+  const { initializeGlobalConsole } = require('internal/console/constructor');
+  initializeGlobalConsole(globalConsole);
+
   // TODO(joyeecheung): most of these should be deprecated and removed,
   // except some that we need to be able to mutate during run time.
   addReadOnlyProcessAlias('_eval', '--eval');
@@ -556,6 +575,7 @@ function loadPreloadModules() {
 }
 
 module.exports = {
+  refreshRuntimeOptions,
   patchProcessObject,
   setupCoverageHooks,
   setupWarningHandler,

lib/internal/bootstrap/switches/is_main_thread.js

@@ -122,27 +122,53 @@ let stdin;
 let stdout;
 let stderr;
 
+let stdoutDestroy;
+let stderrDestroy;
+
+function refreshStdoutOnSigWinch() {
+  stdout._refreshSize();
+}
+
+function refreshStderrOnSigWinch() {
+  stderr._refreshSize();
+}
+
 function getStdout() {
   if (stdout) return stdout;
   stdout = createWritableStdioStream(1);
   stdout.destroySoon = stdout.destroy;
   // Override _destroy so that the fd is never actually closed.
+  stdoutDestroy = stdout._destroy;
   stdout._destroy = dummyDestroy;
   if (stdout.isTTY) {
-    process.on('SIGWINCH', () => stdout._refreshSize());
+    process.on('SIGWINCH', refreshStdoutOnSigWinch);
   }
+
+  internalBinding('mksnapshot').cleanups.push(function cleanupStdout() {
+    stdout._destroy = stdoutDestroy;
+    stdout.destroy();
+    process.removeListener('SIGWINCH', refreshStdoutOnSigWinch);
+    stdout = undefined;
+  });
   return stdout;
 }
 
 function getStderr() {
   if (stderr) return stderr;
   stderr = createWritableStdioStream(2);
   stderr.destroySoon = stderr.destroy;
+  stderrDestroy = stderr._destroy;
   // Override _destroy so that the fd is never actually closed.
   stderr._destroy = dummyDestroy;
   if (stderr.isTTY) {
-    process.on('SIGWINCH', () => stderr._refreshSize());
+    process.on('SIGWINCH', refreshStderrOnSigWinch);
   }
+  internalBinding('mksnapshot').cleanups.push(function cleanupStderr() {
+    stderr._destroy = stderrDestroy;
+    stderr.destroy();
+    process.removeListener('SIGWINCH', refreshStderrOnSigWinch);
+    stderr = undefined;
+  });
   return stderr;
 }
 
@@ -229,6 +255,10 @@ function getStdin() {
     }
   }
 
+  internalBinding('mksnapshot').cleanups.push(function cleanupStdin() {
+    stdin.destroy();
+    stdin = undefined;
+  });
   return stdin;
 }
 

lib/internal/console/constructor.js

@@ -669,9 +669,15 @@ Console.prototype.dirxml = Console.prototype.log;
 Console.prototype.error = Console.prototype.warn;
 Console.prototype.groupCollapsed = Console.prototype.group;
 
+function initializeGlobalConsole(globalConsole) {
+  globalConsole[kBindStreamsLazy](process);
+  globalConsole[kBindProperties](true, 'auto');
+}
+
 module.exports = {
   Console,
   kBindStreamsLazy,
   kBindProperties,
+  initializeGlobalConsole,
   formatTime // exported for tests
 };

lib/internal/console/global.js

@@ -21,9 +21,7 @@ const {
 } = primordials;
 
 const {
-  Console,
-  kBindStreamsLazy,
-  kBindProperties
+  Console
 } = require('internal/console/constructor');
 
 const globalConsole = ObjectCreate({});
@@ -44,9 +42,6 @@ for (const prop of ReflectOwnKeys(Console.prototype)) {
   ReflectDefineProperty(globalConsole, prop, desc);
 }
 
-globalConsole[kBindStreamsLazy](process);
-globalConsole[kBindProperties](true, 'auto');
-
 // This is a legacy feature - the Console constructor is exposed on
 // the global console instance.
 globalConsole.Console = Console;

lib/internal/main/mksnapshot.js

@@ -0,0 +1,143 @@
+'use strict';
+
+const {
+  Error,
+  SafeSet,
+  SafeArrayIterator
+} = primordials;
+
+const binding = internalBinding('mksnapshot');
+const { NativeModule } = require('internal/bootstrap/loaders');
+const {
+  compileSnapshotMain,
+} = binding;
+
+const {
+  getOptionValue
+} = require('internal/options');
+
+const {
+  readFileSync
+} = require('fs');
+
+const supportedModules = new SafeSet(new SafeArrayIterator([
+  // '_http_agent',
+  // '_http_client',
+  // '_http_common',
+  // '_http_incoming',
+  // '_http_outgoing',
+  // '_http_server',
+  '_stream_duplex',
+  '_stream_passthrough',
+  '_stream_readable',
+  '_stream_transform',
+  '_stream_wrap',
+  '_stream_writable',
+  // '_tls_common',
+  // '_tls_wrap',
+  'assert',
+  'assert/strict',
+  // 'async_hooks',
+  'buffer',
+  // 'child_process',
+  // 'cluster',
+  'console',
+  'constants',
+  'crypto',
+  // 'dgram',
+  // 'diagnostics_channel',
+  // 'dns',
+  // 'dns/promises',
+  // 'domain',
+  'events',
+  'fs',
+  'fs/promises',
+  // 'http',
+  // 'http2',
+  // 'https',
+  // 'inspector',
+  // 'module',
+  // 'net',
+  'os',
+  'path',
+  'path/posix',
+  'path/win32',
+  // 'perf_hooks',
+  'process',
+  'punycode',
+  'querystring',
+  // 'readline',
+  // 'repl',
+  'stream',
+  'stream/promises',
+  'string_decoder',
+  'sys',
+  'timers',
+  'timers/promises',
+  // 'tls',
+  // 'trace_events',
+  // 'tty',
+  'url',
+  'util',
+  'util/types',
+  'v8',
+  // 'vm',
+  // 'worker_threads',
+  // 'zlib',
+]));
+
+const warnedModules = new SafeSet();
+function supportedInUserSnapshot(id) {
+  return supportedModules.has(id);
+}
+
+function requireForUserSnapshot(id) {
+  if (!NativeModule.canBeRequiredByUsers(id)) {
+    // eslint-disable-next-line no-restricted-syntax
+    const err = new Error(
+      `Cannot find module '${id}'. `
+    );
+    err.code = 'MODULE_NOT_FOUND';
+    throw err;
+  }
+  if (!supportedInUserSnapshot(id)) {
+    if (!warnedModules.has(id)) {
+      process.emitWarning(
+        `built-in module ${id} is not yet supported in user snapshots`);
+      warnedModules.add(id);
+    }
+  }
+
+  return require(id);
+}
+
+function main() {
+  const {
+    prepareMainThreadExecution
+  } = require('internal/bootstrap/pre_execution');
+
+  prepareMainThreadExecution(true, false);
+  process.on('beforeExit', function runCleanups() {
+    for (const cleanup of binding.cleanups) {
+      cleanup();
+    }
+    process.off('beforeExit', runCleanups);
+  });
+
+  const file = process.argv[1];
+  const path = require('path');
+  const filename = path.resolve(file);
+  const dirname = path.dirname(filename);
+  const source = readFileSync(file, 'utf-8');
+  const snapshotMainFunction = compileSnapshotMain(filename, source);
+
+  if (getOptionValue('--inspect-brk')) {
+    internalBinding('inspector').callAndPauseOnStart(
+      snapshotMainFunction, undefined,
+      requireForUserSnapshot, filename, dirname);
+  } else {
+    snapshotMainFunction(requireForUserSnapshot, filename, dirname);
+  }
+}
+
+main();

lib/internal/options.js

@@ -36,6 +36,11 @@ function getEmbedderOptions() {
   return embedderOptions;
 }
 
+function refreshOptions() {
+  optionsMap = undefined;
+  aliasesMap = undefined;
+}
+
 function getOptionValue(optionName) {
   const options = getCLIOptionsFromBinding();
   if (optionName.startsWith('--no-')) {
@@ -68,5 +73,6 @@ module.exports = {
   },
   getOptionValue,
   getAllowUnauthorized,
-  getEmbedderOptions
+  getEmbedderOptions,
+  refreshOptions
 };